Ferrous alloy



Patented Apr. 23, 1935 UNITED STATES PATENT ore-[cs FERROUS ALLOY Joseph V. Emmons. Shaker Heights; Ohio, as-

signor to The Cleveland Twist Drill Company, Cleveland, Ohio, a'corporation of Ohio 3 Claims.

In my previous U. S. Patent No. 1,937,334 there 5 is disclosed the fact that the addition of tungsten,

to a steel alloy of the type in which molybdenum is the dominating alloying ingredient, in amounts from 5% to 40% of the amount of molybdenum present, has a powerful auxiliary effect far in excess of any effect secured in similar steels without the use of such tungsten.

The present invention relates to the discovery that even smaller proportional amounts of tungsten than contemplated by my above identified patent, particularly when added to alloy compositions in which molybdenum is present in amounts of more than about 6%, have a powerful auxiliary effect upon the alloy, which effect is totally unexpected in that it is much greater than the usual efiiect secured by the use of similar amounts of tungsten in other alloy compositions.

It is the principal object of my invention, therefore, to provide a ferrous alloy of the type in which molybdenum is a principal alloying constituent and to which there has also been added certain minor amounts of tungsten for the production of an alloy composition which, when used in the formation of articles, such as cutting tools, has performance characteristics totally unexpected and superior to those of comparable tungsten-free alloys in the prior art It is a further object of this invention to provide a ferrous alloy composition of the type commonly referred to as high speed steel, including molybdenum as the dominating alloying constituent, which alloying effect is augmented by the cooperation and auxiliary alloying effect of minor amounts of tungsten present in a certain proportional relationship to the amount of molybdenum present.

Other objects of my invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the 'means hereinafter fully described and particularly pointed out in the claims.

The following description sets forth in detail some approved combinations of ingredients embodying my invention, such disclosed means constituting, however, but a few of the various forms in which the principle of the invention may be used. I

Broadly stated, this invention comprises the provision of a ferrous alloy composition in which molybdenum is present in amounts from. about 6% to about 15% and which also includes tungsten in amounts from about 2% to about 4.50% of the amount of molybdenum present.

More particularly, I have found that the alloy composition of the type defined and having the above identified range'of molybdenum present is unexpectedly improved by the addition thereto of tungsten in amounts from about 3% to'4% of the amount of molybdenum present. As will hereinafter appear from a consideration of specific alloy compositions, it will be noted that a preferred embodiment of my invention comprises the use, in an alloy of the character described having molybdenum present in the amounts indicated, of tungsten in amounts about 3.8% or 3.9% of the amount of molybdenum present. The broad limits of composition contemplated by this invention are as follows, viz:

Carbon from about 0.15% to about 1.60%.

Chromium from about none to about 10.00%.

Molybdenum from about 6.00% to about Tungsten from about 0.20% to about 0.70%.

Silicon from a trace to about 3.00%.

Manganese from a trace to about 2.00%.

Vanadium from none to about 5.00%.

Cobalt from none to about 16.00%.

The remainder being substantially iron, together with such other alloying elements and impurities as are sometimes found in this type of alloy composition.

A somewhat narrower range of the limits within which the various elements may be present in the composition contemplated'by this invention is as follows, viz:--

Carbon from about 0.50% to about 1.00%.

Chromium from about 2.00% to about 6.00%.

Molybdenum from about 6.00% 12.00%.

Tungsten from about 0.20% to about 0.54%;

Silicon from about 0.10% to-about 2.00%.

Manganese from about 0.10% to about 1.00%.

Vanadium from about 0.20% to about 3.00%.

Cobalt from none to. about 14.00%. The remainder beings'ubstantially iron together with such other alloying elements and impurities as are sometimes found in this type of alloy composition.

A still narrower range of limits within which the various alloying elements may be present is as follows:

Carbon from about 0.60% to about 0.90%.

to about Chromium from about 3.00% to about 5.00%.

Molybdenum from about 7.00% to about 11.00%.

Tungsten from about 0.20% to about 0.50%. Silicon from about 0.10% to about 1.00%. Manganese from about 0.10% to about 0.60%. Vanadium from about 0.60% to about 2.00%. Cobalt from about none to about 12.00%.

The remainder being substantially irontogether with such other alloying elements and impurities as are sometimes found in this type of alloy composition.

Specific examples of alloy compositions, or

more particularly steels, coming within the above defined limits of composition are as follows, viz:-

% Actual Perc Percent Percent Percent Percent Perce Percent The remainder being substantially iron together with such other alloying elements arid impurities as are sometimes found in this type of alloy composition.

Specific Example No. 5 was found to harden well at temperatures in the range from 2150 F. to 2250 F. Its maximum secondary hardness was attained at tempering temperatures from 1000 F. to 1100 F. When hardened and drawnin these temperature ranges the Rockwell hardness varied from C 64 to C 66.5. In the hardened and tempered condition, the torsional strength was found to be high and the plasticity unusually high indicating exceptional toughness. Twist drills made from this steel showed an excellent performance in drilling, in fact only slightly inferior to that of drills made from 18-4-4 high speed steel with which they were compared. 7

From the foregoing description it will be apparent that my invention relates not to the substitution of tungsten for molybdenum in a molybdenum high speed steel as has been suggested in certain instances in the prior art, but instead, to the production of a new type of molybdenum high speed steel in which a specific minor amount of tungsten is employed for its powerful auxiliary effect in increasing the cutting and wearing qualities of such steel.

By the addition of the auxiliary quantities of tungsten in the above defined specific ratio to the amount of molybdenum present, I have been able to produce a high speed steel of the molybdenum type having cutting properties better than those of tungsten-free molybdenum steels of the prior art.

A wide variety of heat treatments may be employed in connection with the above mentioned steels, including, among others, hardening, tempering, carburizing and nitriding for the purpose of developing specific useful properties in articles made from such steel. It should be noted that the tempering and nitriding operations may, if'desired, be carried out simultaneously. If desired, steels of the above compositions may be deposited as weld metals for the purpose of producing localized cutting or wear-resisting portions of an article of manufacture.

It is, understood that in the composition specified herein, minor amounts of other alloying elements and impurities, such as manganese, nickel, titanium, tantalum, uranium, copper, aluminum, sulphur, phosphorus, arsenic, tin, etc. may be in- 'cluded and when the phrase the remainder being substantially all iron is used, it is intended to include minor amounts of such elements which, for example, may find their way into the composition by being present in the raw materials, particularly scrap, used in making up the composition.

Other forms may be employed embodying the features of my invention instead of the. one here explained, change being made in the composition, provided the elements in the amounts stated by any of the following claims or the equivalent of such stated elements be employed.

I therefore particularly point out and distinctly claim as my invention:--

1. A ferrous alloy comprising: carbon from about 0.15% to about 1.60%; chromium from a substantial amount to about 10.00%; molybdenum from about 6.00% to about 15.00%; tungsten from about two per cent to about four and fifty-hundredths per cent. of the amount of molybdenum present; silicon from a substantial amount to about 3.00%; vanadium from a substantial amount to about 5.00%; cobalt from a substantial amount to about 16.00%; and the remainder being substantially all iron.

2. A ferrous alloy comprising: carbon about 0.76% chromium about4.00% molybdenum about 10.00%; tungsten about 0.20%; vanadium about 1.25%; cobalt about 8.00%; and the remainder being substantially all iron.

3. A tool formed of a ferrous alloy comprising: carbon from about 0.15% to about 1.60%; chromium from a substantial amount to about 10.00% molybdenum from about 6.00% toabout 15.00%; tungsten from about two per cent to about four and fifty-hundredths per cent of the amount of molybdenum present; silicon from a substantial amount to about 3.00%; vanadium from a substantial amount to about 5.00%; colbalt from a substantial amount to about 16.00%; and the remainder being substantially all iron.

JOSEPH v. EMMONS. 

